Kangaroos and other marsupials favor using their left forelimbs over their right

PHOTO: ANDREY GILJOV/NATIONAL GEOGRAPHIC SOCIETY

As most lefties know, we live in a right-handed world. Scientists have long thought that such handedness is largely unique to humans; however, Giljov et al. now report that marsupials show handedness, too. Surprisingly, these wallabies and kangaroos preferred to predominantly use their left forelimbs, rather than their right. Unlike in humans, handedness in marsupials did not correlate with gender, and more bipedal than quadrupedal marsupial species exhibited handedness. Handedness did not associate with phylogenetic relationships between marsupial species, suggesting that ecological adaptations may have driven such preferences. Thus, yet another characteristic thought to be unique to humans falls by the wayside, or rather, to the wallabies.